Such optical modules are used, for example, as signal transmitters or receivers for optical-waveguide transmission links which are used in communication systems to an increasing extent. Light generated in a laser, for example, is coupled into an optical waveguide in the form of a glass fiber, which serves as a transmission medium, and coupled out at the receiving end of the link to an optoelectronic receiver. To minimize coupling losses, the optoelectronic component must be precisely aligned with respect to the end face of the respective light-conducting glass-fiber core. The coupling should be reliable and exhibit long-term and temperature stability.
In prior art transmitter and receiver modules, this requirement is met by costly and complicated precision-mechanical devices (German Patent No. 30 46 415 (corresponding to U.S. Pat. No. 4,296,998), French Published Application No. 2 591 763 (corresponding to U.S. Pat. No. 4,722,586) which must hold very tight tolerances and require high-strength, expensive materials. This adds to the manufacturing costs of the optical components. In addition, their long-term stability is still insufficient.
In CD players, it is known to focus the laser beam, with which the sound information recorded on the disk in digital form is read, on the disk in a vertical direction, i.e., in a direction perpendicular to the disk. This requires a control accuracy of .+-.1 .mu.m. In addition, the pickup unit must be caused to follow the very narrow information tracks on the disk. To this end, the pickup unit is adjusted radially with an accuracy of .+-.0.1 .mu.m ("Neue Audiotechnik aus dem Schwartzwald", Funkschau, No. 4/1986, pp. 30-33; W. H. Lee, "Optical technology for compact disk pickups", Lasers & Optronics, Sept. 1986, pp. 85-87). The necessary accuracies entail considerable expense. Moreover, such prior art pickup units move the laser beam in only one dimension.